Process of treating plastic materials.



' ing or containingmedium while the latter A n d RAYMOND B. IBERICE, OF MISHAWAKA, INDIANA.-

PROCESS or TREATING PLASTIC MATERIALS.

No Drawing.

T 0 all uJ/mmit mayconcern.

Be it known that I, RAYMOND B. PRICE,

.a citizen of the United States, residing at Mishawaka, in the county of St. Joseph, State of Indiana, have invented new and useful Improvements in Processes of Treating Plastic Materials, of which the following is a specification.

My invention relates to the treating of plastic materials, such as rubber and the like, to set the same, and has particular reference to the subjection of the material being treated to the action of the heat conveyis subjected to a pressure greatly in excess of that expansive pressure of said heat conveying or contammg medium which is due .to the application of the treating heat thereto. I

Having particular reference to the employment of a liquid heat-transmitting medium, I have found that a solution of calcium chlorid possesses desirable qualities, and I have also found that Whereas While heretofore a liquid medium has been employed under a comparatively low pressure in excess of its expansive pressure due to the heat, 6. g., a pressure usually approximating pounds, and never, to my knowledge,

exceeding 125 pounds, it is contemplated under my present invention to employ a hydraulic pressure on the solution of calcium chlorid or other liquid medium far in excess of the pressures above mentioned and which may run as high even as 5,000 pounds or more. i

I have found in practice that a pressure I, of 500 pounds has produced results in compacting the material being treated to a much greater degree than under the low pressure heretofore used. In fact it has been found that while under ordinary conditions entrapped air and other fluids more than double in volume under the vulcanizing heat, by using this excessive pressure I not only homogeneous body will be produced. this is true in connection with the useof mediui'ns as calcium chlorid, glycerin, s and sulfur as the heat conveying meiHiD- v I do not, however, wish to be undertood limiting: myself to the use of the enumerated mediums, as my insention con- Specification of Letteis Patent.

Patented se ia 2 1915.

i Application filed January 9. 1912. Serial No, 670,344.

templates the use of any other liqiiid solution, or water, or even a metal bath fusible below the vulcanizing temperature.'

It'will be understood that in employing a liquid medium itv has always been necessary to provide a steam or air space to take care of the expansion of the liquid-under the heat which would otherwise destroy the container, sothat under such conditions the I increase in pressure due to the heating would be comparatively slight, and it is to this expansion that I refer when I speak of the pressure produced by the expansive action of the medium under the heat. In fact, a container holding the material to be set might be filled with a fluid and heated to the setting temperature, provided there be provided in connection therewith an expansion chamber, and by employing a piston or the like in said chamber a controllable pressure greatly in excess of that heretofore employed might be obtained, said pressure greatly exceeding any that would be p'roduced under present customary methods, And this construction would at the same time avoid the use of a large quantity of the surrounding fluid, gas or paste. Nor do I wish to limit my present invention t. .t' use of this abnormally high pressure in connection with a liquid heat conveyin agent, as I contemplate its use, to the extent that it may be possible, in connection with anyknown. gas, such as air or other gas, steam and the like; Or I may surround the article tobe treated with a substance not as fluid as a salt solution, for instance, but one more resembling a slippery powder. such, for instance, as a mixture of powdered talc and glycerin, which could be compressed and in having an affinity for moisture and subjecting the medium to a pressure greatly in excess of that producedhy the expansive action 01' said medium under the heat.

2. The process of vulcanizing plastic ma terial, which consists in surrounding it during the vulounizing operation With a heating medium having an afiinity for moisture and subjecting the medium to a pressure greatly in excess of that produced by the expansive action of said medium under the 'ulcanizing heat. I

3. The process of vulcunizing plastic material consisting of surrounding itduring vulcanization with a fluid medium l'mxving an aflinity for moisture and subjectiiigflhe medium to approximately 500 lbs. pressure.

In testimony whereof, I have hereunto set my hand in the presence of two subscribing witnesses.

' RAYMOND B. PRICE.

Witnesses: 1

A. M. Dlson,

A; R. BOARDMAN. 

